package snapshot_test

import (
	"context"
	"os"
	"path/filepath"
	"slices"
	"testing"

	"github.com/spf13/afero"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"sneak.berlin/go/vaultik/internal/database"
	"sneak.berlin/go/vaultik/internal/snapshot"
)

// A scan records with the snapshot each directory on a different device
// from its parent directory, as a mount point is, the scanned path
// included. A filesystem that gives no device numbers, as the in-memory
// one, records none. See https://git.eeqj.de/sneak/vaultik/issues/395.
func TestScanRecordsMountPoints(t *testing.T) {
	t.Parallel()

	const (
		scannedPath = "/data/source"
		snapshotID  = "mount-points"
	)

	tests := []struct {
		name string
		// onVolume names the directories on the volume's device; every
		// other directory is on another one. nil leaves the device
		// numbers to the in-memory filesystem, which has none.
		onVolume []string
		want     []string
	}{
		{
			name:     "volume below the scanned path",
			onVolume: []string{"nas"},
			want:     []string{scannedPath + "/nas"},
		},
		{
			name:     "volume at the scanned path",
			onVolume: []string{"source", "nas"},
			want:     []string{scannedPath},
		},
		{name: "no device numbers", want: nil},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()

			ctx := context.Background()
			fs := afero.NewMemMapFs()

			for _, path := range []string{
				scannedPath + "/notes.txt", scannedPath + "/nas/a.txt",
			} {
				require.NoError(t, fs.MkdirAll(filepath.Dir(path), 0o755))
				require.NoError(t, afero.WriteFile(fs, path, []byte(path), 0o644))
			}

			db, err := database.NewTestDB()
			require.NoError(t, err)
			t.Cleanup(func() { _ = db.Close() })

			repos := database.NewRepositories(db)
			createTestSnapshotRecord(ctx, t, repos, snapshotID)

			cfg := snapshot.ScannerConfig{
				FS:               fs,
				ChunkSize:        int64(1024 * 16),
				Repositories:     repos,
				MaxBlobSize:      int64(1024 * 1024),
				CompressionLevel: 3,
				AgeRecipients:    []string{testAgePublicKey},
			}
			if tt.onVolume != nil {
				cfg.DeviceNumber = func(info os.FileInfo) (uint64, bool) {
					if slices.Contains(tt.onVolume, info.Name()) {
						return 2, true
					}

					return 1, true
				}
			}

			_, err = snapshot.NewScanner(cfg).Scan(ctx, scannedPath, snapshotID)
			require.NoError(t, err)

			got, err := repos.Snapshots.GetMountPoints(ctx, snapshotID)
			require.NoError(t, err)
			assert.Equal(t, tt.want, got)
		})
	}
}